I don't see any reason in today's world, and the current camera marketplace, which is filled with an excellent and highly diverse selection of cameras of nearly every size and type, all with wonderful IQ, that a person needs to try to put down another brand or camera in order to make their brand of choice look or seem better.

This is a gear forum, it is a please where seemingly non-existent or non-obvious differences get teased out. If this isnt your thing, you can spend your time better else where.

But other people obviously see the whole point behind this exercise. Many, like OP, come here and ask for advice. Others frequently post how they regret buying into a system, or more frequently, asking which other system they should switch to. Getting into a wrong / worse / less optimal system is a very common thing and people like to be better informed to avoid it.

Once you start debating over gear, it is nature that some people are more passionate about what they own than others, it is human nature and you can never separate that from a debate. The completely impassioned debate that you advocate for doesn't even exist in governments and courts, so how it exist in a hobbyist forum?

While it is true all modern systems can produce good results, how easy and how cheap it is for them to achieve good results would vary, and that is the essence of this type of discussion.

Here's the fact that fanboys of any brand hate to hear: ....And most of these interchangeable camera systems will have plenty of lenses that the average user will need not just now, but likely for years to come.

You have gone a bit overboard here. If you like to shoot portrait and want a sharp and and fast 85mm with AF, what option do you have with Sony? Or if you wanted a light weight, super sharp 400mm prime with fast AF for BIF?

Limited lens selection and even more limited secondhand lens market are very significant factors keeping people from buying Sony.